1. Field of the Invention
The present invention relates to a silicon carbide single-crystal substrate and a method for manufacturing the silicon carbide single-crystal substrate, and more particularly to a silicon carbide single-crystal substrate having a peripheral edge portion and a method for manufacturing the silicon carbide single-crystal substrate.
2. Description of the Background Art
A semiconductor substrate is manufactured, for example, by cutting a cylindrical ingot with a wire saw, and grinding and polishing a surface and a peripheral edge portion of a cut substrate. Processing of the peripheral-edge portion of the semiconductor substrate is called beveling processing or chamfering processing.
A method for processing a peripheral edge portion of a silicon wafer is described for example in Japanese Patent Laying-Open No. 9-168947. According to the method, a peripheral edge portion of a silicon wafer is ground by pressing a diamond grindstone against the peripheral edge portion of the silicon wafer and simultaneously applying ultrasonic vibration to the diamond grindstone.
Further, a method for polishing a peripheral edge portion of a nitride semiconductor substrate is described for example in Japanese Patent Laying-Open No. 2009-231833. According to the method, after a back surface of a nitride semiconductor wafer is flattened, a process-damaged layer produced at the back surface is removed by etching, and thereafter a peripheral edge portion of the wafer is ground with a diamond grindstone.